Mallinckrodt Pharmaceuticals (NYSE:MNK) said today that it included the first patient in its Phase IV registry evaluating the use of inhaled Inomax nitric oxide gas for premature neonates compared to term and near-term newborns.

Inomax, which has FDA approval, is designed to boost oxygenation and lessen the need for extracorporeal membrane oxygenation in term and near-term neonates with hypoxic respiratory failure linked to pulmonary hypertension.

The primary outcome measure of the 168-patient registry is slated to compare the incidence of participants with at least a 25% improvement in oxygenation index or surrogate oxygenation index compared to baseline, according to gestation age group.

Mallinckrodt said it expects the observational registry will be completed by 2022.